In response to increasing awareness of the global warming problem in recent years and the rapid increase of the demand of electric power due to rapid economic development in some regions, interest in reduction of loss, particularly, reduction of iron loss (non-load loss) in a transformer increases.
An amorphous magnetic ribbon is practically used as a transformer for distribution using the fact that the non-load loss of the amorphous magnetic ribbon is ⅓ to ¼ of a directional silicon steel plate. A core called a wound core which is formed by winding a magnetic ribbon is generally used for a transformer for which the amorphous magnetic ribbon is used.
However, the wound core of the magnetic ribbon has lower stiffness and is more difficult to be fixed than a stacked core formed by stacking silicon steel plates. Further, if a force applied to the wound core increases, there is a problem in that iron loss increases. With respect to this problem, various proposals have been made.
As a background art of this technical field, there is JP-A-05-144646 (PTL 1). This publication discloses a transformer core which is a wound core constituted by an amorphous magnetic ribbon, has a protecting material constituted by a silicon steel plate attached to peripheries thereof, and is supported by an upper metal fitting and a lower metal fitting.
Also, there is JP-A-62-238612 (PTL 2). This publication discloses a transformer core which is formed by winding an amorphous magnetic ribbon around a winding frame of a core and has a pair of side plates having a rectangular frame shape disposed so as to surround the core.
Further, there is JP-UM-A-63-15022 (PTL 3). This publication discloses a transformer core which is a wound core constituted by an amorphous magnetic ribbon and is fixed to a side clamp.